1. Field of the Invention
The present invention relates to an Enhanced-Multicast Broadcast Services (E-MBS) in a wireless communication system. More particularly, the present invention relates to an apparatus and a method for switching to a dedicated carrier for an E-MBS in a wireless communication system that uses a multi-carrier.
2. Description of the Related Art
As broadband wireless networks that provide an Internet service in a mobile environment are rapidly distributed, expectation for a new application based on this technology increases. One application receiving attention is a multimedia streaming service. Where many users receive the same multimedia service (for example, news, sports live relay) at the same time, when a point-to-point channel is used to transmit multimedia data to each of multimedia service users, a radio resource having a large amount of bandwidth is required.
To efficiently transmit a multimedia service to many users simultaneously in view of resources and costs, most standardization research organizations are developing standards for functional architecture to support an efficient multicast/broadcast service at a network level. For example, the 3rd Generation Partnership Project (3GPP) and the 3GPP2 standardization organizations have already defined a Multimedia Broadcast/Multicast Service (MBMS) architecture and a Broadcast/Multicast Service (BCMCS), respectively. Similarly, the WiMAX forum that defines a network architecture for a broadband wireless access network based on IEEE 802.16 defines an architecture for an Enhanced-Multicast Broadcast Service (E-MBS).
As an important concept of IEEE 802.16e standardization, seamless broadcast service is provided using an E-MBS zone. The E-MBS zone binds a plurality of base stations and provides the service to the same service area. In the same E-MBS zone, a terminal shares multicast parameters, and may omit a resetting procedure and perform a service even when the terminal moves to another base station.
An IEEE 802.16m system supports a multi-carrier environment that can perform transmission or reception using a plurality of carriers defined as predetermined bandwidths. A base station and a terminal may be defined to perform transmission/reception using only independent carriers, respectively, or may be configured to perform transmission/reception at a wide band formed through aggregation of a plurality of carriers. Respective carriers may be successively arranged or disposed apart from each other on a frequency. The configuration of a set may change statically or dynamically. For the IEEE 802.16m system to efficiently distribute resources, the IEEE 802.16m system performs a service using an exclusive carrier for an E-MBS.
However, a wireless communication system that uses a multi-carrier such as the IEEE 802.16m system does not define a specific E-MBS service procedure for an E-MBS under an environment where a service is provided using an exclusive E-MBS carrier. Accordingly, an apparatus and a method for a multicast broadcast service in a wireless communication system that uses a multi-carrier are desired.